#include "widget.h"

float vertices[] = {
    // positions          // colors           // texture coords
     0.5f,  0.5f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f, // top right
     0.5f, -0.5f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f, // bottom right
    -0.5f, -0.5f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f, // bottom left
    -0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 0.0f,   0.0f, 1.0f  // top left
};
unsigned int indices[] = {
    0, 1, 3, // first triangle
    1, 2, 3  // second triangle
};


MyGLWidget::~MyGLWidget()
{
    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glDeleteBuffers(1, &EBO);
}

void MyGLWidget::initializeGL()
{
    initializeOpenGLFunctions(); // 初始化 OpenGL 函数

    //创建、绑定VAO
    glGenVertexArrays(1, &VAO);
    glBindVertexArray(VAO);

    //创建、绑定VBO + 填充数据
    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

    //设置顶点属性指针
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);

    // 颜色属性
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3* sizeof(float)));
    glEnableVertexAttribArray(1);

    //纹理坐标
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
    glEnableVertexAttribArray(2);

    //解绑缓冲区和 VAO
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);

    shader = new Shader(":/shader/shader.vert", ":/shader/shader.frag");

    //创建、绑定纹理
    texture1 = loadTexture(":/img/container.png", false);
#if 1
    texture2 = loadTexture(":/img/awesomeface.png");

    // 绑定着色器程序
    shader->bind();
    // 设置纹理采样器
    shader->setUniformValue("texture1", 0); // 设置采样器 texture1 到纹理单元 0
    shader->setUniformValue("texture2", 1); // 设置采样器 texture2 到纹理单元 1
#endif

    QTimer *timer = new QTimer(this);
    connect(timer, &QTimer::timeout, this, [&]
    {
        this->update();
    });
    timer->start(100);
}

void MyGLWidget::paintGL()
{
    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT); // 清除颜色缓冲区

    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texture1);
#if 1
    glActiveTexture(GL_TEXTURE1); // 激活纹理单元 1
    glBindTexture(GL_TEXTURE_2D, texture2); // 绑定第二个纹理
#endif
    QMatrix4x4 matrix;
    unsigned int time=QTime::currentTime().msec();
    matrix.translate(0.5,-0.5,0);
    matrix.rotate(time, 0.0f, 0.0f, 1.0f);

    shader->bind();

    // 设置着色器中的矩阵变量
    shader->setUniformValue("transform", matrix);

    glBindVertexArray(VAO);
    //glDrawArrays(GL_TRIANGLES, 0, 3);
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

    matrix.setToIdentity();
    matrix.translate(-0.5,0.5,0);
    matrix.rotate(time, 0.0f, 0.0f, 1.0f);
    matrix.scale(fabs(sin(time)));
    shader->setUniformValue("transform", matrix);
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

    glBindVertexArray(0);
}

void MyGLWidget::resizeGL(int w, int h)
{
    glViewport(0, 0, w, h); // 设置视口大小
}

unsigned int MyGLWidget::loadTexture(const char *fileName, bool alpha)
{
    unsigned int texture;
    glGenTextures(1, &texture); // 生成纹理 ID
    glBindTexture(GL_TEXTURE_2D, texture); // 绑定纹理

    // 设置纹理参数
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
#if 0
    // 加载图片并转换为 OpenGL 格式
    QImage image;
    if (!image.load(fileName))
    {
        qWarning() << "Failed to load texture image";
        return 0;
    }
    image = QGLWidget::convertToGLFormat(image); // 转换为 OpenGL 格式
    unsigned char *data = image.bits();
    // 生成纹理
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.width(), image.height(), 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D); // 生成多级渐远纹理
#else

    QFile file(fileName);
    file.copy(file.fileName(), QFileInfo(file).fileName());

    int width, height, nrChannels;
    stbi_set_flip_vertically_on_load(true); // tell stb_image.h to flip loaded texture's on the y-axis.
    unsigned char *data = stbi_load(QFileInfo(file).fileName().toStdString().c_str(), &width, &height, &nrChannels, 0);
    if (data)//awesomeface  container
    {
        if(alpha)
            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
        else
            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
        glGenerateMipmap(GL_TEXTURE_2D);
    }
    else
    {
        std::cout << "Failed to load texture1" << std::endl;
    }
    stbi_image_free(data);
#endif
    return texture;
}
